Portable tools with selective means for locking spindle



Feb. 3, 1959 R. HAPPE 2,872,197

PORTABLE TOOLS WITH SELECTIVE MEANS FOR LOOKING SPINDLE Filed Sept. 10, 1957 nuunnum mam .6 .5

X INVENTOIR.

Reynold Happe WITNESS Fig4 By 2 WM 7' I v ATTORNEY United States Patent M PORTABLE TOOLS WITH SELECTIVE MEANS FOR LOCKING SPINDLE Reynold Happe, Princeton, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application September 10, 1957, Serial No. 683,095 6 Claims. c1. 279-1 This invention relates to portable tools having power take-off spindles threaded to receive screw-on tool-holding elements and more particularly relates to selective means for locking said spindles against rotation'to facilitate the removal of the tool holding elements.

it is frequently desirable, for example, to conveniently remove the conventional key chuck from thepower spindle of portable electric drills to enable other elements to be attached as desired. The competitive compactness of present-day portable electric drills is .such that the chuck is screwed up against the inner race of the spindle bearing with the result that the spindle cannot be reached externally for holding relative to the chuck. Thus many schemes have been devisedfor operating through the tool case to hold stationary something internally in the power transmission between the motor rotorend .the

spindle. Sometimes the motor rotor shaft itself ishelcl cant withoiit detriment to the free operation holdirig means. This has generally b'e'en attemptedheretofore by the use of a manually operated plunger working in an aperture in the gear casing and has required either close running its or long leakage paths both of which are undesirably expensive and not always durable inasmuch as the efiectiveness of the seal is directly and adversely affected by normal frictional wear between the plunger and the aperture.

It is a primary object of this invention therefore, to provide a selective locking means for a portable tool spindle in which a plunger is journaled for reciprocatory movement in an aperture in a gear casing and in which a lubricant seal is substantially unaffected by possible wear between the plunger and the aperture.

It is a further object of this invention to provide a selective locking means for a portable tool spindle having manual means operative through an aperture in said tool and means independent of said manual means for sealing said aperture against the leakage of lubricants.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

in the drawings,

.Fig. l is a longitudinal sectional view taken through a portable tool embodying the present invention.

Fig. 2 is a partial sectional view taken substantially on the line 22 of Fig. 1.

Fig. 3 is an elevational view taken substantially on atented Feb. 3, 1959 lCC the line 3-3 of Fig. l with the gear casing cover removed.

Fig. 4 is a front-end elevational view of the device of Fig. 1.

Referring to Fig. 1 there is shown a portable electric drill having an open face gear casing 19, a casing cover 11, and a motor casing 12 assembled in interfitted relation and secured by screws 13 to form a portable tool body. This type of drill is shown and described in greater detail in the U. S. Patent No. 2,456,571, to which reference may be had for a more complete understanding of the parts.

A rotor shaft 14 of an electric motor 15 is journaled in a bearing 16 secured in the cover 11 and is formed with a splined portion 17 which meshes with a spur gear 18 having a common shaft connection with a smaller pinion gear 19. The pinion gear 19 meshes with a spur gear 20 formed with a threaded external spindle 21 journaled in a bearing 22 carried by an apertured portion of the gear casing 10. A conventional key-type chuck 23 is screwed onto the spindle 21 and seats against the inner race of the bearing 22 so that, with the chuck 23 in place, no part of the spindle 21 is accessible from the exterior.

Thus, if it were attempted to unscrew the chuck 23 to remove it from the spindle 21, the spindle would merely turn backwards as there is nothing to prevent it from so doing, and no relative motion between the chuck and spindle would result. Sometimes a quick impulse application of reverse turning movement is applied to the chuck and, if the inertia of the gear train and rotor is suificient to supply enough resisting torque, the chuck may be unscrewed. However, this method cannot be relied on and it becomes necessary to apply some more convenient and positive means for selectively locking the spindle, against rotation.

In the present invention this locking means takes the following form:

Located within the gear casing 10 is a boss 24 formed with'a recessed seat 25 as seen best in Pig. 2. Received in said seat 25 is one end of a rigid arm 25 containing an aperture 27 through which passes a screw 28 threaded into the boss 24. A spacing bushing 29 carried on the screw 28 establishes the amount of compression of a spring 3% which surmounts the bushing 29 and urges the arm 26 against the seat 25 which is inclined as shown. The opposite end of the arm 26 carries a pin 31 adapted to enter any one of several apertures 32 formed in the gear 18. Normally, due to the inclination of the seat 25, the arm 26 is biased by the spring 3% to hold the pin 31 out of engageable position with respect to the apertures 32, as shown in the full lines of Fig. 2.

The front wall of the gear casing 10 is formed with a recessed portion 33 containing an aperture 34. Mounted for reciprocatory movement in the aperture is a plunger formed from an outer headed element 35 and an inner headed element 36 having their respective shank portions 37 and 38 telescoped in press fitted engagement. A guide pin 39 pressed into the inner element 36 freely engages a pilot aperture ill in the arm 26, while the inner element itself bears against the arm. A washer 41 made of resilient oil-resistant material is located between the inner headed element and the recessed portion of the wall as clearly shown in Figs. 1 and 2.

It is evident that, in the normal position of the parts, the washer 41 is compressed and serves as an effective seal against leakage of lubricant through the annular space defined by the fit of the plunger in the aperture 34. It is also clear that any possible frictional wear between plunger and aperture does not adversely alfect the washer as a sealing element. The sealing function of this structure is independent of the operating function.

The outer headed element 35 is normally substantially flush with the outer surface of the gear casing 10 and so is not likely to be pushed in accidentally nor does it detract from the stream-lined appearance of the drill as a whole. The three-part plunger makes it a simple matter to push the elements 35, 36 and 39 together and form at once a plunger captive in the wall of the gea casing. 1 p

In operation, the outer element 35 is pushed in causing the inner element 36 to press against the arm 26 to overcome the bias of spring 30 and move the arm 26 to the right as viewed in Fig. 2. If an aperture 32 in the gear 18 is aligned with the pin 31, the pin will enter the aperture and lock the gear and hence the spindle 21 against rotation. In this condition the chuck 23 may be readily unscrewed.

If an aperture 32 in the gear 18 is not aligned with the pin 31, it is merely necessary to rotate the chuck 23 to move the gear 18 until alignment is made, keeping pressure on the element 35 so that the pin will engage the aperture as shown in the dotted lines in Fig. 2.

I do not intend to be limited to the details shown and described, except as they are required by the intended limitations of the appended claims.

Having thus described the nature of the invention, what I claim herein is:

1. In a gear casing for a portable tool, an external power take-0E spindle journaled in said casing, a toolholding chuck threaded on said spindle, a train of gears within said casing for driving said spindle, one of said gears being formed with face apertures, a pin for engaging any one of said apertures, said pin being carried at the free end of a cantilever-supported arm located within said casing and normally biased to a disengaged position of the pin, and separate manually-operated means extending freely through an aperture in the wall of the gear casing for overcoming said bias to engage said pin with one of said apertures to lock the gear train against rotation to facilitate the removal of the chuck by unscrewing it from the spindle.

2. Apparatus in accordance with claim 1 in which the manually-operated means comprises an endwise reciprocatory element formed with a stem portion freely journaled in the wall of said casing, an enlarged head portion in operative contact with said arm and a resilient Washer embracing the stem portion between the head and the casing wall to form a seal against leakage of lubricant in the non-operated position of said arm.

3. A gear lock for a portable tool comprising an internal gear-engaging element carried on the free end of a cantilever-supported arm, means located entirely within said tool for normally biasing said element out of gear-engaging position, separate manual means operative through an aperture in said tool to overcome said bias,

and resilient means located adjacent said aperture effective responsively to compression normally applied thereto by the biasing meansfor sealing said aperture against leakage of lubricant.

4. Apparatus in accordance with claim 3 in which said manual means is formed at one end with a guide pin which engages a pilot aperture in the cantilever-supported arm and at the other end with a push button operated externally of the tool.

5. Apparatus in accordance with claim 1 in which said manually-operated means comprises external and internal headed elements having telescoping shank portions press-fitted together, whereby said headed elements stand on opposite sides of the gear casing wall, the external element forming a push button, and the internal element forming a pusher for actuating said cantileversupported arm.

6. Apparatus in accordance with claim 5 in which a resilient annular washer held between said internal headed element and the casing wall is normally compressed by said biasing means to form a seal for preventing the escape of lubricant through said casing aperture.

References Cited in the file of this patent UNITED STATES PATENTS 1,649,060 Decker Nov. 15, 1927 2,702,098 Staak Feb. 15, 1955 2,716,555 Rowe Aug. 30, 1955 

